A Deep Dive into Common Indoor Molds

Mold. Just the word conjures up images of damp, dark spaces and potential health hazards. But did you know there are many different types of mold, each with its own unique characteristics and potential effects?

Here at Sani Effect, we believe knowledge is power. That’s why we’ve compiled this comprehensive guide to common indoor molds. Understanding the types of mold, where they thrive, and their potential health impacts can help you take proactive steps to protect your home and your health.

1. Acremonium

• Found in: Soils, decaying organic matter, plant debris, and as an agricultural contaminant. Indoors, it requires extremely wet conditions.
• Appearance: Compact and moist colonies, often white, gray, or rose-colored, with a cottony texture.
• Health Effects: Can cause allergies and produce toxins. Associated with nausea, vomiting, diarrhea, and various infections.

2. Alternaria

• Found in: Outdoor air, carpets, textiles, window frames, soil, seeds, and plants.
• Appearance: Rapidly growing colonies, initially grayish-white, turning greenish-black or olive-brown with a light border. Dry spores easily become airborne.
• Health Effects: Common allergen linked to hypersensitivity pneumonia, respiratory issues, skin sores, and nail infections.

3. Arthrinium

• Found in: Dead plants, especially grasses. Often isolated from air near grassy places in autumn.
• Appearance: Rapidly growing, woolly or cottony colonies, white with brown spots.
• Health Effects: Generally not considered a significant health risk, with only one species known to be allergenic.

4. Ascospores

• Found in: Various environments, including damp indoor materials.
• Appearance: Highly variable in size and shape.
• Health Effects: Some can be allergens or opportunistic pathogens.

5. Aspergillus

• Found in: Textiles, organic materials, soil, plant debris, water-damaged building materials, and often in water-damaged carpet.
• Appearance: Woolly or cottony texture, with shades of green, brown, or black. Spores are similar to Penicillium.
• Health Effects: Can cause aspergillosis, especially in individuals with weakened immune systems. Many species produce mycotoxins, some of which are carcinogenic.

6. Aureobasidium

• Found in: Moist indoor areas like bathrooms and kitchens, shower curtains, window sills, and textiles.
• Appearance: Yeast-like, starting cream or pink, and turning dark brown with age.
• Health Effects: Common allergen, causing Type I allergies and hypersensitivity pneumonitis.

7. Basidiospores

• Found in: Gardens, forests, and woodlands.
• Appearance: Sexual spores released from the basidium of a fungus. Can cause dry wood rot.
• Health Effects: Common allergen. May produce toxins.

8. Bipolaris

• Found in: Plant debris, grasses, soil, and semi-dry environments.
• Appearance: Rapidly growing colonies, initially white to grayish-brown, turning olive green to black.
• Health Effects: Can produce mycotoxins, causing liver and kidney damage. Associated with phaeohyphomycosis and allergic fungal sinusitis.

9. Cercospora

• Found in: Outdoor agricultural areas.
• Appearance: Distinctive spores, not easily confused with other types.
• Health Effects: Produces no known toxins.

10. Chaetomium

• Found in: Damp or water-damaged building materials, especially paper in sheetrock.
• Appearance: Rapidly growing colonies, initially white, turning gray to olive with age.
• Health Effects: Allergenic, can cause hay fever and asthma. Associated with phaeohyphomycosis and in rare cases, brain abscess and other infections. May cause neurological damage and has been linked to autoimmune diseases.

11. Cladosporium

• Found in: Outdoor air, dead plants, food, paint, textiles, and dirty refrigerators.
• Appearance: Relatively slow-growing, powdery or velvety olive-green to olive-brown colonies.
• Health Effects: Common cause of hay fever and asthma.

12. Curvularia

• Found in: Plant debris, soil, and stored grains.
• Appearance: Rapidly growing, woolly colonies, initially white to pinkish-gray, turning olive brown or black.
• Health Effects: Allergenic and can cause corneal infections, mycetoma, and infections in immunocompromised individuals.

13. Dictyosporium

• Found in: Terrestrial and freshwater habitats.
• Appearance: Dark brown, green-black, or black colonies.
• Health Effects: No information available on allergenicity or toxicity.

14. Drechslera

• Found in: Plant debris, soil, and various indoor substances in tropical and subtropical areas.
• Appearance: Rapidly growing colonies, initially white, becoming olive brown to black.
• Health Effects: One of the most common allergenic molds. Can also produce toxins.

15. Epicoccum

• Found in: Plants, soil, grains, textiles, paper products, and house dust.
• Appearance: Rapidly growing, woolly colonies, initially yellow, orange, or red, turning greenish-brown to black.
• Health Effects: Allergen associated with respiratory issues.

16. Eurotium

• Found in: Stored seeds, textiles, leather, and furniture.
• Appearance: Whitish to bright yellow spherical fruiting bodies.
• Health Effects: Closely related to Aspergillus in terms of health effects.

17. Fusarium

• Found in: Soil, plants, grains, and humidifiers.
• Appearance: Rapidly growing colonies with various colors, including white, tan, pink, and purple.
• Health Effects: Allergenic and associated with eye, skin, and nail infections. Produces trichothecene toxins, which can affect various body systems.

18. Myxomycetes

• Found in: Forested areas, bark, soil, and leaf litter. Occasionally found indoors.
• Appearance: Not a true fungus, exhibiting characteristics of both protozoans and fungi.
• Health Effects: Produces no known toxins.

19. Nigrospora

• Found in: Decaying plant material and soil, especially in warm climates.
• Appearance: White, woolly colonies that turn gray and eventually black.
• Health Effects: Allergenic, with rare cases of human infection.

20. Odium

• Found in: Leaves, stems, flowers, and fruits of living plants.
• Appearance: White powdery spots.
• Health Effects: No information available on health effects, toxicity, or allergenicity.

21. Penicillium

• Found in: Soil, food, cellulose, paint, grains, carpet, wallpaper, and fiberglass duct insulation.
• Appearance: Rapidly growing colonies, initially white, turning blue-green, gray-green, or yellow.
• Health Effects: Allergenic and can cause hypersensitivity pneumonitis. Some species produce mycotoxins and carcinogens.

22. Periconia

• Found in: Soil, dead plant stems, and grasses. Rarely found indoors.
• Appearance: Difficult to distinguish from other round, brown spore types.
• Health Effects: Occasionally implicated in mycotic keratitis.

23. Pestalotiopsis

• Found in: Leaves, stems, and bark of plants. Can grow on polyurethane.
• Appearance: Gray spot or lesion on plants.
• Health Effects: No information available on health effects, toxicity, or allergenicity.

24. Pithomyces

• Found in: Decaying plants, grasses, and soil. May grow on paper but is not prolific indoors.
• Appearance: Tan to brown colonies.
• Health Effects: Allergenic and can be pathogenic in animals, causing liver damage.

25. Polythrincium

• Found in: Leaves and dust. Not known to grow indoors.
• Appearance: Not well known.
• Health Effects: No information available on health effects, toxicity, or allergenicity.

26. Rusts

• Found in: Grasses, flowers, and trees. Do not grow indoors unless their host plants are present.
• Appearance: Red, rusty, or orange spores.
• Health Effects: Type I allergen.

27. Scopulariopsis

• Found in: Soil, decaying wood, drywall, wallpaper, and carpets.
• Appearance: Moderately fast-growing colonies, initially white, becoming light brown or tan.
• Health Effects: Very little is known about the health effects.

28. Smuts

• Found in: Corn, grass, and other plants. Not usually found indoors.
• Appearance: Black, powdery spore masses.
• Health Effects: Type I allergens.

29. Spegazzinia

• Found in: Soil and dead plant material, especially in warm climates.
• Appearance: Slow-growing, brownish-black to black colonies.
• Health Effects: No mycotoxin production or pathogenicity in humans is reported. Allergenicity effects have not been studied.

30. Sporothrix

• Found in: Soil, damp wood, living or decomposing plants, and peat moss.
• Appearance: At 25°C, colonies are moist, leathery to velvety, and white, becoming cream to dark brown. At 37°C, colonies are yeast-like and creamy.
• Health Effects: Can cause sporotrichosis, a chronic fungal infection, primarily in immunocompromised individuals.

31. Stachybotrys

• Found in: Water-damaged cellulose-rich materials like sheetrock, paper, and ceiling tiles.
• Appearance: Cottony, rapidly growing colonies, initially white, turning dark green and black. Shiny when wet.
• Health Effects: Produces highly toxic mycotoxins. Exposure can cause dermatitis, respiratory problems, immune suppression, and even death.

32. Stemphylium

• Found in: Soil, wood, decaying vegetation, and dust.
• Appearance: Rapidly growing colonies, velvety to cottony, gray, brown, or brownish-black.
• Health Effects: Known Type I allergen.

33. Tetraploa

• Found in: Leaf bases and stems of plants and trees.
• Appearance: Brownish colonies.
• Health Effects: Rare cases of keratitis and subcutaneous infection reported.

34. Torula

• Found in: Soil, dead wood, leaves, food, hay, textiles, and indoor cellulose-based materials.
• Appearance: Light grayish-brown and powdery.
• Health Effects: Type I allergen and a possible cause of hay fever and asthma.

35. Ulocladium

• Found in: Plant materials, soil, drywall, and other organic materials indoors.
• Appearance: Moderately fast-growing colonies, olive-brown, rusty-brown, black, or grayish.
• Health Effects: Major allergen, causing hay fever and asthma. Rarely causes subcutaneous infections.

36. Yeast

• Found in: Various habitats, including plant leaves, soil, salt water, and the skin and intestinal tracts of animals.
• Appearance: Rapidly growing, smooth, and pasty colonies, typically white to cream-colored.
• Health Effects: Can cause various infections, from skin lesions to systemic mycoses. Some yeasts are allergenic.

37. Zygomycetes

• Found in: Soil or decaying plant and animal material.
• Appearance: Common, fast-growing, and often overgrow other fungi.
• Health Effects: Known allergens, produce toxins, and can cause adverse health effects.

Understanding these common indoor molds is the first step in protecting your health and maintaining a clean and safe home environment. Regularly inspect your home for signs of mold, especially in areas prone to moisture, and address any issues promptly. If you suspect a mold problem, consult with a professional mold remediation specialist like Sani Effect to assess the situation and recommend appropriate solutions.